/**
 * An abstract class for fields that have a single trigger which opens a "picker" popup below the field, e.g. a combobox
 * menu list or a date picker. It provides a base implementation for toggling the picker's visibility when the trigger
 * is clicked, as well as keyboard navigation and some basic events. Sizing and alignment of the picker can be
 * controlled via the {@link #matchFieldWidth} and {@link #pickerAlign}/{@link #pickerOffset} config properties
 * respectively.
 *
 * You would not normally use this class directly, but instead use it as the parent class for a specific picker field
 * implementation. Subclasses must implement the {@link #createPicker} method to create a picker component appropriate
 * for the field.
 */
Ext.define('Ext.form.field.Picker', {
    extend: 'Ext.form.field.Trigger',
    alias: 'widget.pickerfield',
    alternateClassName: 'Ext.form.Picker',
    requires: ['Ext.util.KeyNav'],

    /**
     * @cfg {Boolean} matchFieldWidth
     * Whether the picker dropdown's width should be explicitly set to match the width of the field. Defaults to true.
     */
    matchFieldWidth: true,

    /**
     * @cfg {String} pickerAlign
     * The {@link Ext.Element#alignTo alignment position} with which to align the picker. Defaults to "tl-bl?"
     */
    pickerAlign: 'tl-bl?',

    /**
     * @cfg {Number[]} pickerOffset
     * An offset [x,y] to use in addition to the {@link #pickerAlign} when positioning the picker.
     * Defaults to undefined.
     */

    /**
     * @cfg {String} [openCls='x-pickerfield-open']
     * A class to be added to the field's {@link #bodyEl} element when the picker is opened.
     */
    openCls: Ext.baseCSSPrefix + 'pickerfield-open',

    /**
     * @property {Boolean} isExpanded
     * True if the picker is currently expanded, false if not.
     */

    /**
     * @cfg {Boolean} editable
     * False to prevent the user from typing text directly into the field; the field can only have its value set via
     * selecting a value from the picker. In this state, the picker can also be opened by clicking directly on the input
     * field itself.
     */
    editable: true,


    initComponent: function() {
        this.callParent();

        // Custom events
        this.addEvents(
            /**
             * @event expand
             * Fires when the field's picker is expanded.
             * @param {Ext.form.field.Picker} field This field instance
             */
            'expand',
            /**
             * @event collapse
             * Fires when the field's picker is collapsed.
             * @param {Ext.form.field.Picker} field This field instance
             */
            'collapse',
            /**
             * @event select
             * Fires when a value is selected via the picker.
             * @param {Ext.form.field.Picker} field This field instance
             * @param {Object} value The value that was selected. The exact type of this value is dependent on
             * the individual field and picker implementations.
             */
            'select'
        );
    },


    initEvents: function() {
        var me = this;
        me.callParent();

        // Add handlers for keys to expand/collapse the picker
        me.keyNav = new Ext.util.KeyNav(me.inputEl, {
            down: me.onDownArrow,
            esc: {
                handler: me.onEsc,
                scope: me,
                defaultEventAction: false
            },
            scope: me,
            forceKeyDown: true
        });

        // Non-editable allows opening the picker by clicking the field
        if (!me.editable) {
            me.mon(me.inputEl, 'click', me.onTriggerClick, me);
        }

        // Disable native browser autocomplete
        if (Ext.isGecko) {
            me.inputEl.dom.setAttribute('autocomplete', 'off');
        }
    },

    // private
    onEsc: function(e) {
        // Only stop the ESC key event if it's not going to bubble up to the FocusManager
        if (!Ext.FocusManager || !Ext.FocusManager.enabled) {
            e.stopEvent();
        }
        this.collapse();
    },

    onDownArrow: function(e) {
        if (!this.isExpanded) {
            // Don't call expand() directly as there may be additional processing involved before
            // expanding, e.g. in the case of a ComboBox query.
            this.onTriggerClick();
        }
    },

    /**
     * Expands this field's picker dropdown.
     */
    expand: function() {
        var me = this,
            bodyEl, picker, collapseIf;

        if (me.rendered && !me.isExpanded && !me.isDestroyed) {
            bodyEl = me.bodyEl;
            picker = me.getPicker();
            collapseIf = me.collapseIf;

            // show the picker and set isExpanded flag
            picker.show();
            me.isExpanded = true;
            me.alignPicker();
            bodyEl.addCls(me.openCls);

            // monitor clicking and mousewheel
            me.mon(Ext.getDoc(), {
                mousewheel: collapseIf,
                mousedown: collapseIf,
                scope: me
            });
            Ext.EventManager.onWindowResize(me.alignPicker, me);
            me.fireEvent('expand', me);
            me.onExpand();
        }
    },

    onExpand: Ext.emptyFn,

    /**
     * Aligns the picker to the input element
     * @protected
     */
    alignPicker: function() {
        var me = this,
            picker = me.getPicker();

        if (me.isExpanded) {
            if (me.matchFieldWidth) {
                // Auto the height (it will be constrained by min and max width) unless there are no records to display.
                picker.setWidth(me.bodyEl.getWidth());
            }
            if (picker.isFloating()) {
                me.doAlign();
            }
        }
    },

    /**
     * Performs the alignment on the picker using the class defaults
     * @private
     */
    doAlign: function(){
        var me = this,
            picker = me.picker,
            aboveSfx = '-above',
            isAbove;

        me.picker.alignTo(me.inputEl, me.pickerAlign, me.pickerOffset);
        // add the {openCls}-above class if the picker was aligned above
        // the field due to hitting the bottom of the viewport
        isAbove = picker.el.getY() < me.inputEl.getY();
        me.bodyEl[isAbove ? 'addCls' : 'removeCls'](me.openCls + aboveSfx);
        picker[isAbove ? 'addCls' : 'removeCls'](picker.baseCls + aboveSfx);
    },

    /**
     * Collapses this field's picker dropdown.
     */
    collapse: function() {
        if (this.isExpanded && !this.isDestroyed) {
            var me = this,
                openCls = me.openCls,
                picker = me.picker,
                doc = Ext.getDoc(),
                collapseIf = me.collapseIf,
                aboveSfx = '-above';

            // hide the picker and set isExpanded flag
            picker.hide();
            me.isExpanded = false;

            // remove the openCls
            me.bodyEl.removeCls([openCls, openCls + aboveSfx]);
            picker.el.removeCls(picker.baseCls + aboveSfx);

            // remove event listeners
            doc.un('mousewheel', collapseIf, me);
            doc.un('mousedown', collapseIf, me);
            Ext.EventManager.removeResizeListener(me.alignPicker, me);
            me.fireEvent('collapse', me);
            me.onCollapse();
        }
    },

    onCollapse: Ext.emptyFn,


    /**
     * @private
     * Runs on mousewheel and mousedown of doc to check to see if we should collapse the picker
     */
    collapseIf: function(e) {
        var me = this;
        if (!me.isDestroyed && !e.within(me.bodyEl, false, true) && !e.within(me.picker.el, false, true)) {
            me.collapse();
        }
    },

    /**
     * Returns a reference to the picker component for this field, creating it if necessary by
     * calling {@link #createPicker}.
     * @return {Ext.Component} The picker component
     */
    getPicker: function() {
        var me = this;
        return me.picker || (me.picker = me.createPicker());
    },

    /**
     * @method
     * Creates and returns the component to be used as this field's picker. Must be implemented by subclasses of Picker.
     * The current field should also be passed as a configuration option to the picker component as the pickerField
     * property.
     */
    createPicker: Ext.emptyFn,

    /**
     * Handles the trigger click; by default toggles between expanding and collapsing the picker component.
     * @protected
     */
    onTriggerClick: function() {
        var me = this;
        if (!me.readOnly && !me.disabled) {
            if (me.isExpanded) {
                me.collapse();
            } else {
                me.expand();
            }
            me.inputEl.focus();
        }
    },

    mimicBlur: function(e) {
        var me = this,
            picker = me.picker;
        // ignore mousedown events within the picker element
        if (!picker || !e.within(picker.el, false, true)) {
            me.callParent(arguments);
        }
    },

    onDestroy : function(){
        var me = this,
            picker = me.picker;

        Ext.EventManager.removeResizeListener(me.alignPicker, me);
        Ext.destroy(me.keyNav);
        if (picker) {
            delete picker.pickerField;
            picker.destroy();
        }
        me.callParent();
    }

});

